Under that new rule, pitchers can only be removed from a game without facing at least three batters in the event of injury or illness at the crew chief's discretion. The rule will be implemented during spring training on March 12. Spring games are set to begin Feb. 21.

The active roster size has also been changed from 25 to 26 players. September rosters will allow for 28 players as opposed to the previous 40-man rule.

Additionally, teams will be allowed to designate "two-way" players, who both pitch and play a position/act as the designated hitter. In order to qualify for the two-way designation, a player must throw at least 20 MLB innings and make 20 MLB starts at any position while recording at least three plate appearances in each of those starts. Players who may receive that designation in 2020 include Los Angeles Angels star Shohei Ohtani and Cincinnati Reds outfielder/reliever Michael Lorenzen.

Due to the two-way rule, players without the designation will be unable to pitch in games that have either not reached extra innings or feature a score differential of more than six runs.

This season, the 10-day injured list has been changed back to the 15-day IL. The 10-day IL was introduced prior to the 2017 season. However, after teams appeared to exploit the shorter timeline with their pitchers, the league is returning to the 15-day list that was originally introduced in 1966.

Meanwhile, managers will be afforded less time to decide on whether or not to challenge a play. Umpires will enforce a 20-second timer instead of the previous 30-second rule.